Contact bank for automatic switches in telephone systems



sTEMs K. NOACK oct. 14, 1941.

CONTACT BANK FOR AUTOMATIC SWITCHES IN TELEPHONE SY Filed May 18, 1939 r Illllllll ullums` lllll UIII 4-1- `IIIIIIIIIIIIIIII /NVENTO K14/PL NOACK i 11,4

atented ct. 14, 1941 CONTACT BANK FOR AUTOMATIC SWITCH- ES IN TELEPHONE SYSTEMS Karl Noack, Berlin-Friedenau, Germany, assignor to Fides Gesellschaft fr die Verwaltung und Verwertung von gewerblichen Schutzrechten mit beschrnkter Haftung, Berlin, Germany, a

corporation of Germany Application May 18, 1939, Serial No. 274,373 In Germany May 27, 1938 (Cl. F75-306) 1 Claim.

This invention relates to laminated contact banks, more particularly to contact banks for automatic switches in telephone installations, in which the contact segments are arranged between layers of the insulating material.

In contact banks of the type to which reference has been made, hollow spaces exist between the adjacent contact segments in the horizontal contact rows, in which dust and metal chips may collect and cause short circuits, this action being fostered by the lubrication of the contact segments or contact arms. In order to avoid this undesirable effect it has already been proposed to seal the interstices by means of strips or tubular members extending over the full height of the laminated structure and being held, by friction between the segments at the front face of the bank. This proposal involves the yuse of additional means for obtaining the desired result.

According to the present invention the air gaps between adjacent contact segments are closed by shoulders or projections provided upon the intermediate insulating layers, i. e. without special additional means being provided. The dimensions oi these projections may be such that the projections cover a part only of the apertures of the cavities, so that for completely sealing a cavity two such projections i. e. one on each side of a segment, are required, or, alternatively, one only of the two intermediate layers is provided with a projection of corresponding size. The sealing of the cavities is, therefore, much simplified and is effected by the intermediate insulating layers, without additional elements being used. As this particular form of the intermediate layers can most conveniently be produced during the manufacture of these layers, the sealing of the cavities can be accomplished, according to this present invention, without any increase of the manufacturing costs.

The invention is now described with reference to the accompanying drawing which illustrates, on an increased scale, an embodiment of the in- Vention.

Fig. 1 is a front view of a fragment of a contact bank,

Fig. 2 is a. plan View, the cover plate having been removed.

In both gures the contact segments of the bank are designated by I. These contact segments are arranged in rows or levels, each row of contact segments being clamped in any desired manner between two ilat strips of suitable insulating material 2. Those portions of the insulating layers which pass over or under the spaces between the segments l are so stamped out that they project into the intermediate spaces, and form projections or shoulders 4 which seal the front apertures of the cavities. Metal dust which may adhere to the side faces of the segments, and lubricant and the like substances are prevented from collecting between the intermediate layers 2 by this construction of the intermediate layers so that short circuits do not occur. As shown in the drawing, the opening between two contact segments l may be closed by stamping into the opening a portion 4 of the insulators 2 disposed on both sides of the contact segments. The same eiect may also be obtained, as stated, by one only of the two intermediate layers, which are arranged one on each side of the segments l, being protided with a projection or shoulder 4 of adequate size.

I claim:

In a Contact bank, two supports, a row of spaced apart Contact terminals clamped betwen said two supports, each contact having a portion lying under one edge of one of said supports and another portion projecting beyond said one edge, said one support formed from a flat sheet of insulating material and having a plurality of tongues along said one edge, each tongue bent downwardly between two adjacent ones of said contact terminals to substantially close the opening between said two contacts.

KARL NOACK. 

